Stimulatory Effect of Whey Syrup on Growth of Lactic Acid Bacteria and Lactic Acid Fermentation

Abstract

　Whey syrup, prepared by immobilized β-galactosidase, and whey were added separately to 10% skim milk culture media, and then incubated with 2% of a fresh culture starter of Lactobacillus delbrueckii subsp. bulgaricus at 37℃ for 24 hr. The growth of Lb. bulgaricus and change in acidity were observed during the incubation. The addition of whey syrup and whey both stimulated the growth of Lb. bulgaricus in the skim milk culture media. However, the addition of whey syrup was more effective than that of whey. The lag phase of growth of Lb. bulgaricus with the addition of whey syrup was 2 hr shorter than that with the addition of whey. When whey syrup and whey were added to skim milk culture media, the acidities were higher than the control sample during incubation, suggesting that both whey syrup and whey had a good stimulatory effect on lactic acid fermentation. Furthermore, the lactic acid production was higher with the addition of whey syrup than with the addition of whey within the logarithmic phase of growth of Lb. bulgaricus. The results show that the whey syrup is a better substrate than whey for stimulating lactic acid fermentation.